Soluble pouches, particularly ostomy pouches, are known which may be discarded and dissolved (or dispersed) in the water of a common toilet bowl and in the discharge lines of a water-disposal system. One type of such a pouch is at least partially formed of pH-sensitive material so that an alkali or acidic agent can be added to the toilet bowl to initiate dissolution of the pouch (see U.K. patent application GB 2,201,372A and U.S. Pat. No. 4,620,999). Another type of known flushable pouch is constructed of a pair of side walls that are each composed of at least two layers, specifically, a tough, flexible, but water-soluble or water-dispersible primary layer, which gives the pouch its structural integrity and a thin, water-insoluble inner layer which lines the inside of the pouch and prevents the pouch's contents from contacting and dissolving the primary layer when the pouch is worn (see U.S. Pat. Nos. 4,772,279 and 4,917,688). For effective results, both types of pouches typically require a waiting interval between the time a pouch is discarded in the bowl and the time the toilet is flushed; otherwise, the pouch may not have dissolved sufficiently to be discharged by the flushing operation and might even cause at least temporary obstruction of the toilet and/or waste discharge lines. It is therefore believed that some type of flush-interval indicator would be useful to help prevent a user from prematurely flushing a toilet after discarding a pouch in the toilet bowl and also to inform the user when a sufficient time interval has elapsed and further waiting is unnecessary. The time period of such a flush-interval will vary depending upon the particular type of soluble pouch involved but, in general, a waiting period of at least 30 seconds, but not exceeding 5 minutes, preferably no more that 3 minutes, is typical. It is believed that any type of flush-interval indicator that would require effort or active participation on the user's part would tend to be ineffective because of inconvenience and resulting non-use. Such considerations render unrealistic any sort of timing mechanism or accessory that would be operated by the user such as providing the user with a chemical that, when poured into the toilet bowl, would change color after a sufficient flush-interval has elapsed.
An important aspect of this invention therefore lies in providing a relatively uncomplicated flush-interval indicator that does not require any active participation on the part of the user and is self-contained in that the indicator is integral with the pouch and does not require the user to carry any additional timing means, chemical packets, or the like. Such a flush-interval indicator comprises a flushable, soluble pouch having a pair of side walls joined together along their outer margins and having a display surface on at least one of its side walls. An optically-distinguishable flush indicator is printed upon or otherwise affixed to a display surface of the pouch for visibly indicating to a user when a sufficient flush-interval has elapsed after the user has discarded a pouch in a toilet bowl. The indicator may take the form of words such as "READY", "FLUSH", or the like, which provide a visible signal to the user when the pouch should be flushed. A water-soluble concealing means is positioned to shield the indicator from view when the pouch is dry. However, the concealing means, when exposed to water in a toilet bowl for an interval of about 30 seconds to a maximum of 5 minutes, preferably no longer than 3 minutes, is capable of dissolving or dispersing sufficiently to reveal the flush indicator.
In one embodiment, the flushable pouch is constructed of a pair of side walls that are each comprised of a primary layer of strong but water-soluble material capable of quickly dissolving in the water of a toilet bowl and a protective inner layer of relatively weak but water-insoluble material which protects the primary layer from the contents of the pouch. In that embodiment, the flush indicator is printed on the water-insoluble inner layer, and the concealing means comprises a water-soluble primary layer which is opaque or contains a pigment to render it opaque. When a user discards the pouch in a toilet bowl, the water-soluble primary layer sufficiently dissolves or disperses, after a predetermined interval, to reveal the indicator printed upon the inner layer, thereby visibly signaling the user that the toilet may be safely flushed. Such a construction is particularly effective as the flush-interval, the time it takes for the opaque layer to dissolve, coincides with the dissolution or dispersion of the primary layer of the pouch, and the indicator is only revealed once the pouch is in such a condition that it may be safely and effectively flushed away. In other embodiments, the side walls of the pouch may be formed of only a single layer and it may not be possible to use a water-soluble layer of the pouch itself as the means for concealing an indicator on the pouch. For such pouches, the concealing means may comprise an opaque external panel secured to the pouch to cover and shield the indicator from view when the opaque layer is dry. Depending upon the particular construction of the soluble pouch, the external panel may be made of material that will dissolve, when exposed to water, in a time period that corresponds with the interval needed for the soluble pouch to break down to such a degree that it may be effectively flushed away. Once again, it is believed that a time period of at least 30 seconds is desirable and, in some instances, such period may extend up to 3-5 minutes. The external panel may be formed of a cellulosic material, such as opaque paper. However, tissue paper has been found to be particularly effective as it is highly absorbent and hydrophilic in nature, which is believed to enhance the rate of dissolution of the pouch as it ensures that water in the toilet bowl is brought into and maintained in close contact with the pouch side walls. Forming the external panel of tissue paper is also advantageous in that it promotes patient comfort by providing a soft, absorbent layer next to the skin when the pouch is worn. It is also believed that such a tissue layer, when the toilet is flushed, helps to overcome film buoyancy problems by entrapping and pulling the pouch film, or fragments of pouch film, which may otherwise tend to float, into the discharge lines of the water-disposal system.
In an alternate construction, the side walls of the pouch may be formed of single or multiple layers and the concealing means comprises an opaque external cover formed of fibers which is secured to the pouch over a display surface provided by at least one of the side walls. The fibrous cover is adapted to quickly dissolve or disperse, after a sufficient flush-interval has elapsed, when exposed to water in a toilet bowl. The flush indicator is formed on the display surface of the pouch by embedding fibers of the cover into the display surface, preferably with a heat seal, to define a word such as "FLUSH", "READY", or the like. The indicator word is not distinguishable while the cover is in a dry state but, after the pouch has been discarded in the water of a toilet bowl and the external cover has sufficiently dissolved or dispersed, the fibers remaining embedded in the pouch provide a visible and legible indicator to signal the user that the pouch may be safely flushed.
Other features, advantages, and objects of the invention will become apparent from the specification and drawings.